1. Field of the Invention
The present invention relates to a mucosa-regulating material so-called tissue conditioner used in odontotherapy and, more particularly, to a mucosa-regulating material for denture wearers suffering from intra-oral mucosa deformation or mucositis.
2. Background Art
For a powdery component of tissue conditioners now commercially available, polymers based on poly ethyl methacrylate or copolymers of vinyl chloride with vinyl acetate are used, whereas for a liquid component, a mixed liquid of a plasticizer such as butyl phthalyl butyl glycolate (BPBG for short) with ethanol is employed.
For using the tissue conditioner, the powdery component is mixed with the liquid component to obtain a mixture, which is then cast up on the mucosal side of a denture plate. The denture plate is inserted into the oral cavity in which sophisticated contact of the mixture with the mucosal side of the denture plate is regulated over a time, while keeping it flowable thereon. At the time of curing, the tissue conditioner is separated from the mucosal side of the denture plate, and the mucosal side after treatment is substituted by a fresh denture plate material to make the completed denture plate.
The essential conditions required for the tissue conditioner after the mixing of the powdery component with the liquid component are that:
(1) a tissue conditioner should maintain its combined elastic/viscous properties in the oral cavity over an extended period of time, and
(2) a tissue conditioner should possess an adhesion strength sufficient for allowing it to remain bonded to the surface of a denture plate over an extended period of time.
In order to cure the mixture meeting both (1) and (2) within a time usually allowed for clinical handling, however, it was generally inevitable to use ethanol as one liquid component. In other words, ethanol served to swell the powdery component and so increase its affinity with respect to the plasticizer of the liquid components, thereby achieving rapid gelling of the mixture after mixing.
Thus, ethanol was essentially required as one liquid component of tissue conditioners, but was a troublesome material for patients, because when used in the form of a liquid component containing ethanol, it gave stimuli to the intra-oral mucosae of patients, dissolved in saliva or emitted an ethanolic odor uncomfortable for patients.
When used with a denture plate formed of a material based on methyl methacrylate (MMA), ethanol of the liquid component solubilizes the surface of a denture plate or swells itself enough to deform or crack the denture plate. Thus, the denture plate is so decreased in strength or so solubilized on separating-off after curing that it is mechanically bonded to a tissue conditioner, often making its separation difficult.
Thus, to use ethanol as one liquid ingredient poses a problem to both patients and clinicians.
As a result of intensive studies made to solve such problems of tissue conditioners as mentioned above, the present inventors have successfully invented a novel dental composition. More specifically, the dental composition according to the present invention comprises a powdery component consisting of either one of a copolymer of butyl methacrylate with ethyl methacrylate and a mixture of poly butyl methacrylate (PBMA for short) with poly ethyl methacrylate (PEMA for short) and a liquid component consisting of at least one of butyl phthalyl butyl glycolate (BPBG) without ethanol, dibutyl phthalate (DBP), benzyl butyl phthalate, benzyl benzoate, ethyl benzoate, butyl benzoate and amyl benzoate, said powdery and liquid components being mixed or kneaded together for use.
According to the present invention, it has now been found that if the copolymer of butyl methacrylate with ethyl methacrylate or the mixture of PBMA with PEMA is used as the powdery component, a dental composition having its physical properties much more improved than those of tissue conditioners heretofore available can then be obtained even without allowing ethanol to be contained as the liquid component in a plasticizer.